Rotating wing aircraft



Sept. 27, 19 38. I R QHAFNER 11 3 ROTATING WING AIRCRAFT- v V '7 Filed July 27, 1935 Patented Sept. I 27,

Raoul Hai'ner," Vienna, Aust i-ia 1-; J I I Application July" 27,1935, Serial No. 33,462

I In Great Britain November 9, 1934 I I I 4 Claims. (01.1244-60) This invention, relates to aircraft or thekind having a rotating wing system, hereinafter called a rotor, in which the said rotor is positively driven by the engine or in which a drive from the engine clutch device which transmits torque to the rotor at a ratio increasing in correspondence to the 1| increasing speed of the driven member thereof and the rotor and becomes rigid, when the rotation of the rotor exceeds a predetermined value. Among the various forms of couplings or clutch devices fulfilling the above requirement may be mentioned the centrifugal type and particularly I the devices using powdered material or shot. In operation this apparatus-automatically ensuresthat. at low speeds ofthe rotor, when the centrifugal force is insufiicient to maintain the 5 blades in approximately radial disposition against other influences, the maximum torque applied to the hub shall not be sufiicient to cause strain or damage in the blade roots or their mountings, whereas as the rotor picks up speed the slip in the system is diminished and the torque transmitted is suitably increased.

This desirable effect is not, of course, achieved by using overload-relief couplings adapted to slip at predetermined fixed values of torque, independently oi the speed of the system. In such a cases the pilot has to exercise considerable caution in engaging the main clutch to avoid overload at low speeds, whereas'in the present case this is not called for. In fact the main clutch .in aircraft according to the invention may obviously be of a simple and light positively-engag-' 'in g kind, such as a dog clutch, without incurring any risk of over-acceleration of the rotor when starting.

The invention is described with reference to the accompanying drawing, whereinthe'only figure shows diagrammatically the clutch and the control levers in isometric projection.

The axially fixed portion I of a dog clutch is 5 mounted upon a driving shaft 2 and the other portion 3 of thesaid clutch is slidably mounted on a squared portion 4 of the driven shaft 5. This shaft 5 is connected to one portion 9 of a shot or powder clutch the outer case in of which is provided with a gear ring which engages a body of the machine and is connected spur wheel 1 on; o. short 8 g omig with the rotor While theldrawingshows the 'paddleconnected 1 I to the drivingshaft'and' the case inengag'enient'; with the driven shaft, it is obvious that the desired eifect could also be obtained if the paddle 5 would be connected with the driven 'shaft and the case with the driving shaft. The movable portion 3 of the do'gclutch is controlled by a I-: pedal: lever 9 and a spring! 0 is provided to keep the said pedal normally inthe raised position'lo with the two parts I, l disengaged. 9

On the right hand side of the, D dallever 9 is" mounted a pedal lever 29 which controls the wheel brakes. Thesaid lever is provided'with a projection no extending "behind the back; our

the lever 9 so that the lever 9 cannot be depressed without applying the wheel brakes. The wheel brakes, however, may b appnedwithout t g I, I III I I I in the clutch.

To the left of the pedal lever 9 is mounteda i pedal lever I! which is connected .to the rotor .I

brake. This lever has a fixed pawl "adapted toengage teeth in'a ratchet quadrant ll whichis pivoted atone end I! to afixed'portion of the I other. end It to a link 11 which is pivoted at its 'lower end to,a projection i9 from the lever 9.

The quadrant is normally held in engagement with the pawl by a spring l9 connected to-a fixed I portion of the body ofthe machine.

. With this mechanism when the clutch lever 9 is depressed toengage-the clutch I, 9 the lever.

s engages the projection I and applies the wheel Y I brakes. At the same time the projection 19 on 1 the lever 9 by means of the link I 1 pulls down ,35 I

theba'ck end I8 of the quadrant ll against the action of the spring l9 and releases the quadrant l2 and the rotor brake. I I

Thus the clutch cannot be thrown in while'the o rotor brake is. on or whilethe wheel brakes are off. a

When theclutch I, 3 is engaged the two portions of ,the fluid flywheel 6, to move relatively I4 and pawl I3 thereby releasing the pedallever I to one another transmitting a limited torque. 45 I I until, the rotor has been speeded up.

If desired, instead of theclutch lever 9 being at all times urged outwardly by the spring it, it

may have associated therewith an over-centre or spring toggle mechanism'so that it will r e 50; main in the depressedposition until, positively I dislodged therefrom, thereby relie'vingthe pilot of the necessity oi holding-it down during the speeding up 01' the rotor.f With-such an arrangement it would be of advantage to have the lever s What 1 claim an desire to secure by Letters Patent'of the United States is:-

1. In a rotative wing aircraft means for transmitting power from the engine to the rotor including a coupling device having a driving member, a. driven member, and centrifugal clutch means arranged on the'j drivenmember to increase the degree of engagement between the" driven member and the driving member in dependence upon the increase in the angular velocity of the driven member, whereby at any given speed of the .driven member the coupling slips when the torque to be transmitted. exceeds a maximum predetermined value relative to said speed. r

2. A device, as claimed in claim 1, in'which said coupling device is a centrifugal clutch having apulverulent torque transmission medium.

3. Means for transmitting power from the prime mover to the supportingrrotor of a rotary wing aircraft to accelerate said rotor mini rest," comprising a clutch device having driving and. driven members and centrifugal means responsive to increase in speed of said driven member, substantially irrespective of the speed of said driving member, forincreasing the degree of engagement 0! said members and consequently to increase the maximum torque transmissible to said rotor by said clutch device.

4. Means ytor transmitting power from the prime mover to the1supportingrotor of a rotary wing aircraft to accelerate said rotor from rest, comprising a clutch device having driving and drivenmembers and centrifugal means to regulate' the degree or engagement of said clutch dc vice and consequently the maximum torque transmissible thereby to said rotor, saidcentrii'ugal means being carried round by said driven member so as to proportion said maximum transmissible torque to the speed of the rotor rather than to that of the prime mover.

' RAOUL-HAFNER. 

